Furnace



P. c. LOTTES FURNACE Feb. 6, 1940.

2' Sheets-Sheet 1 Filed June 16, 1938 INVENTQR Paul C. LOZles.

ATTORN EY P. C. LOTTES Feb; 6 I940.

FURNACE Filed June 16, 1938 2 Sheets-Sheet 2 Fig. 4.

TTEP? Fig 5.

I WITNESSES: EIAWAEW JMJL.

INVENTOR Paul Ci'ottes.

ATTORNEY Patented Feb. 6, 1940 UNITED STATES FURNACE Paul G. Lottcs, Wilkin sburg, Pa.,'assignor to Westinghouse Electric & Manufacturing Company, East Pittsburgh, "Pa., a corporation of Pennsylvania Application June 16, 1938, Serial No. 214L031" -11Claim's. (Cl. 263-10) My invention relates generally to electric furnaces of the type having, a heatingchainber in which a charge is treated While it is enveloped by protective gaseous atmosphere within theheating am r In processes for the heat treatment of metals, and by the term metals I intend toinclude alloys, it has been found necessary to envelop the metal by a protective gaseous atmosphere inorder to prevent deleterious effects upon the. metal by reaction thereof 1 with active gaseous components that would otherwise contact the metal. 'I'he composition of such aprotective atmosphere will p nq r e the n o meta b in ted and the treatment applied to it, as is well known in the j h In many of theprocesses, evenrelatively min uteamounts ,of air contain agents which react with the 'metal to the detrimentof the final prodnot in that thelast m ay/be tarnishedQor scaled, or have some other objectionable feature, 'Ijhe protective atmosphere can besuccessively treated to contain only the constituents .des red. But {crifrigt sit not a cnarge'int or the r mpval'thereo fjf the' furnace the opening of ummw De. .1 ,1 r to enter into thelheat: h mi eeuarde a n I :int pose an additional, safe,-

f of 1 ;air into :the heating .l bp icab to ance chamber,

er ea n -c amber', for the'charg'e. It-is customary in such fur naces to purge thisauxiliary chamber of air i or was in hb... 1i c t the m .lze' u i '.mq i lished br' br jecting' the tun-11am chamber to a' flow of the Pr t t ve h e 1' t l th a os ,S,have beendriven ou Anauxiliary chamber H of this 'sort necessarily has two. doors}. one

. .9 was cl s d-1,1 chb ei t ilen 1 wanted air to get' into. the mainfheating jcham-h be and m nventi n b oad or the purpose of preventing .thefopening of one dopr while the Qt eris q sn ateq' ri, e he .WQ'rd .r perdo bejopenipnly'while theother I nm ida Uea t n. adde factor of 'saf ttfinthe operationfof a furnace suchas has been just described, although. it should be distinctly understood that my invention has many other applications. It is, accordingly, a'nobj ect of my invention to provide two doors of a furnace with positive in? terlock so that one can be opened Jonly while the other isclosed. l It is a further object ofrmy invention topmvide in a furnace having a main heatingchambar, a mechanism inuthe nature of interlocked doors to insure" .that theheatingchamber is always ly c o eld... H It is still another object of my invention to provide operating mechanisms for. two. doors which can be independently operatedfrom a sin gle convenient location.

I It is a further purpose of; my inventionto' provide an interlock; for two operating mechanisms asaforesaid. which can be selectively. operatedin W It is still another obj ect ofj my invention to provide, adjusting structure for. the interlock whereby it will always be operable regardlessof changing dimensions of the door operating means with time. c

These and other objectsvo'f my invention will be apparent from the following description there! of/taken in conjunction with thedrawings, in

which.', f a Figure 1 is a view, representative. in horizontal section and plan,'of a furnace to which my invention may be applied.

Fig. 2 is a front view. .oi the door. operating mechanisms and interlock.

Fig. 3 is. a sectional View taken. along the line III-III of Fig. 2 with both ,doorsshown forthe purpose of better illustrating my invention. This figure shows the interlock in one position, whereby one door is lockedagainst movement.

Fig. 4 is a sectionalview showing the intere lock in a second position wherebythe second door is locked against movement.

Fig. 5 is a side View of a modified interlock-l ing mechanism. v a v I I Fig. 6 is a sectional view taken along the lines VI-VI of Fig. 5.

The furnace I shownin Fig. 1 is. representative of the furnace to which my invention can be applied, but it is to be distinctly understood that my dooroperating means and interlock is not limited to this particular typeof furnace. The furnace t has a heating chamber 3 within which are heating units 3 which in this instance are energized by electrical power. At one side of the furnace of the heating chamber is an auxiliary chamber 5 and on the other side isa second.

auxiliary chamber 7. The auxiliary chambers are separated from a main heating chamber 3 by appropriate intermediate fire walls having apertures closed by doors 9 and H for the chambers 5 and 1, respectively.

The auxiliary chamber 5 in this particular. instance is shown as a charge entrance chamber,

that is, it is a chamber in which the charge is. placed preparatory to its heat treatment. The chamber 1, on the other hand, is the charge exit chamber.

chamber 1 may be employed as a cooling chamber. v I v The chamber 5 has an opening 13 through which the charge is inserted and this opening is closed by door l5. The chamber 1 is similar in this respect to the chamber 5 and has an opening I 1 controlled by a door l9. A push rod 2! sliding in packed journal 23 serves to push the charge from the entrance chamber to the heating chamber 3, while a pull rod 25 sliding in packed journal 21 serves to pull the charge from the heating chamber. to the exit chamber 1. In order to insure fairly tight gas seals between the doors and the door jambs (not shown) any of the common expedients may be used, as for example, the doors 9 and I l are shown as inclined. with the walls with which they cooperate similarly inclined. I In operation, each of the chambers mayhave pipes (not shown) by which a protective atmosphere is led to each, chamber and is conducted away therefrom. When it is desired to start the furnace, the doors 9 and H are placed in closed position and preferably also the door l9. With the chambers 3 and 1 thus enclosed, the former or both are purged of air by admitting the protective gas atmosphere under pressure for a definite time period. charge ma be placed in thefchamber ii. whereuponthe doo I is then closed and this chamber also purged of a r.

When the air has been eliminated from the chambert to the desired degree, heat may be applied and the door 9 opened when the desired temperature in, chamber3 is reached. A push rod 2! then. serves to pushthe charge into. the heating chamber 3, after whichthe door 9 is then closed. While the charge isbeing heat treated, a second charge may be inserted into the furnace chamber 5 which is then again pur ed preparatory to the opening of door 9 to admit the second charge to the heat treating chamber. A sufficient number of charges are placed into the heat reating chamber 3 in accordance with its dimen ions: When it is desired to withdraw the charge after its heat treatment, the reverse procedure is followed, that is, the chamber 1 is purged of air,

the door H. is opened and the pull rod 25 pulls capable of either pushing the charge or with- If desired the chamber 5 may also be employedas a preheating. chamber while the exit furnace may have conveyors insteadcf relying on rods 2| and 25, all as is well knownto the art.-

The operating mechanisms and their interlock for the doors 9 and I5 are the same as-that for the doors I! and l9except that the parts are.

reversed to accommodate the different arrangements of the doors.

For the purposes of this description,1 therefore, oneon'lyrof'thej operating mechanisms need be described. 1

one of their ends'attached. to the door 5! so as to raise and lower it. The turning of the handle 29 turns the shaft 33 to; cause the door it to be to rotate therewith is a beveled gear s1 meshing with a second beveled gear 49 to which is secured a shaft 5|. The shaft 5!. is supportedat' one end by a bearing within asupport fi3fsecured tothe furnace wall or any other stationary structure while the other end of the shaft 5i may be additionally supportedby a bearing in a support (not shown) also secured to the furnace vwall or other 2 stationary structure. Aretainer guide which additionally serves to'maintainthelshafts in proper cooperative relation is u shapedin form, as shown, and. has three apertures through which the shafts 33, .45 and. 5!, respectively, extend;

wheels 51 over which pass sprocket chains 59 L having one of their ends secured to the door l5. To raise and lower the door l5,handle 4| may be rotated. Rotation of the handle 4| turns the disk 43 which, in 'turn',.revolves theshaft 45 and 1 bevel gear 41 about the shaft33. Rotation of the bevel gear causes rotation of .the .bevel gear 49 meshing therewith, and this,fin turn, rotates the shaft 5| whereupon the door l5is raised or lowered through operation of the sprocket mechanism'.. 1 i

In order to insurethat one ofthe doors 9 or IE5 will be closed at all times', I.provide an interlockcomprising a stationary. support Bl! having a rod 6| secured thereto. Slidingon this rod is a hollow handle 63 moving an elongated plate 65 unitary with. the. handle {and interposed between the two disks. The plate 65 at' theend opposite the handle 63 is'forkedas shown at B'Ifto straddle the shaft 33,. andis therebymaintained in posia length somewhat greater than the spacefl5' between the disks 3!. and 43. @However, a protruding end of the lug 13.plu s' the thickness of the plate is less than this space 15.

In order to lock thedoors', the apertures "69 and. H are so spaced as to be aligned only when the doors a and I5 are in their closed position. If i now it is desired to open one of the doors, thhan dle 63 is moved so that the lug I3 enters the aperture of the disk associated with'the'otherdoor. In Fig. 3 is shown the position of the mechanism with the door |'5 closed. It may be observed that the lug 13'is in the aperture 69 of the disk 43 and thereby prevents rotation of this disk inasmuch as any attempt to move the handle will tend to rotate the plate 65. However, because of the lug |3 ,and, therod 6|, this plate cannot beretated so that-the door |5"*is maintained closed, but inasmuch as the other end of the lug 13 is now clear of the disk 3|, the latter can be rotated to controlthe door 9. .The fork 6 provides an additional means to prevent'r'otatio'n of"plate"', and this fork therefore permits greater clearancebetween lugs 13 and its associated apertures.

Fig. 4 shows the position of the interlock when it is desired to maintain "the door 9 closed and permit control of the door |5 in which case the lug 13 is moved by means of handle63 so that it enters aperture H and is free of the disk 43.

It may thus be seen that by my interlocked doors, an operator cannot open both doors at one time and furthermore it may be observed that since one of the doors 9 and I5 is always closed and one of the doors H and I9 is also always closed, the heating chamber 3 is at all times fully inclosed.

The mechanism just described for the inter locking of the doors is applicable only where the opening or closing of the doors, can be accomplished by less than a completerevolution for the reason that the handle 4| cannot be rotated through a complete circle because of the interpositioned plate 55, and thehandle 29can be deliberately made with a portion I6 (Fig, 1) protruding in the rear of disk 3| so that the plate 65 will interfere with its complete rotation in case the door jamb does not limit the travel of the door to the necessary extents. However, to per,- mit a greater mechanical advantage in opening and closing the doors, I may employ the structures shown in Figs. 5 and 6. 1

.In thisstructure, the shafts 33, 45 and the mechanism connected thereto towards the doors is identical with the structure previously described However, disks 3| and43', corresponding to the disks 3| andI43, need not be provided with apertures. Upon the shaft 45 is provided anadditional gear 11 which rotates therewith, and upon the shaft 33 is provided an additional gear 19 which rotates with the shaft 33. A fixed support 3| has a base plate 83 to which are attached two extending supporting members 85 and 81, and in these supporting members is journalled a stationary shaft 89.

Loosely mounted for free rotation on the shaft 89 area disc in the form of the gear 9|' meshing Wth gear H and a second disk in the form of the gear 93 meshing with gear 19. Apertures are provided in the gears 9| and 93 into which may extend the lug F3 in a manner similar to that described for the previous modificaltion. The apertures are aligned only when the doors 9 and l5 are in closed position, but because of the reand 93 are limited to movement in an arc of less than 360 degrees. If the number of revolutions r'quired tomdveofie or the oors betwe'enits ex- 'trem'e "positions" greater than the number of revolutions required to move the other door between-"its extreme positions, this may be additionally taken "care" of by changing the ratio between "a' p'air ofg'earsll and.- 9| or '|9 and 93', as w owelug*-|3"is secured in a platef95-so as' to be moved 'whenthe plate '95 is moved, A rod9| is attacliedfto the plate95 and maybe pushed in either direction to" lock whichever gear, 9 For 9-3;it may be desired to'lock, The rod 91 rests upon the" bottom: of curved surfaces 99 of plates '9 l and 93'secur1e'd tothe baseplate 83 below the gears-s1 and 93 respectively. Theimembers |0| l'fi3f' fu'rth'er serveas indicating means in conjunction: with index pointer fingers and 19"! secured to the gears 9| and 93, respectively;

The plate 191" as an "index arrow I09 which, whemali'gned with the finger I05 shows the position o'fvthefgear 9l {with the door' l5'clo'sed, and a similararroW' on the member I03 cooperates with theindex finger lflltoindicate the proper position of the gear 93 when the'door 9 is closed. *In orderthat these indicators shall be accurate-and 't'o-f'compensate for discrepancies in the{ door operatingmechanism which may occur during assembly-or in the course of time due,

' for example, to elongation of the sprocket chains,

I-provide"an adjusting means for the gears 9| and- 93'. This means comprises twovwashers HI and. H3 secured to the shaft 89, and compres- Jsio'n springs-H5 and H1 normally urging the gears 9| and 93 into position wherein theymesh with their respective gears-"11' and 19. However,

"eitherof the goars el 'andSS-may be slid along shaft 89 'against the pressure of the springs {I I5 and '||l until they are out of mesh' with the gears on 'the f'shafts 33' and 45. When the doors are in 'closed' position, the gears 9| and i93 with"theirfindex fingers aligned'on the inf dicator arrows'f rnay be releasedfto engage the gears li and so that theindicatorsautomati callyfshow the correct vposition of .these gears with the doors Closed. 'As described in the first modificatio ngfthe lug-13" is of; a length somewhat greatef'than th e distancebetween the gears 9| and 93, and for adjustment purposes it is prefferable to so position the lug 13' that the ends thereof are partially within the apertures in both the gears so that both doors can be locked. "While I'hav'e described my invention in the embodiments which I believe to be the best mode doors, and an interlock permitting operation of either one of said doors only while the other is in a predetermined position.

2. In combination, a rotatable shaft, a rotatable disc means secured to said shaft, a handle for rotating said disc means, a second shaft,

a second rotatable disc means loosely mounted I on said first shaft and connected to said second shaft for rotating the latter, a handle for r0 tating said second disc means, said discs being I spaced apart and substantially parallel, and in- 75' terlocldng rneansjin such ,space for locking one oi s aid disc means at all times lwhile the other is be n r ed.- I

;3. .'The structure defined in claim 2 wherein said last means comprises apertures in each of said discs which are aligned at ,a predetermined position of said discs, a pin of a length some what greater than said space, and means preventing rotation of saidpin and for sliding said pin into one or the other-of said apertures.

- 4. In a furnace chamber comprising two doors, an operating means; for one of said doors and comprising-a shaft and adisc means secured to said shaftfor rotating said shaft, an'operating means for the other of said doors and comprising a rotatable discfmeans loosely mounted on said shaft, said disc means being spaced from each other, and each having apertures which are aligned when said doors are closed, a vpin between said discslideable-in saidapertures and of a length somewhat greater than said space, and means preventing said pin fromrotating and for sliding saidpin intoone or the other of both of said apertures. v I 5. A furnace comprising a heating :chamber and a secondarychamber, a commonnwall betweensaid chambers comprisingla doonra second door for-said secondary chamber substantially at right angles to said first door; a shaft -having an inner portion .insaid secondary. chamber and an outside protruding portion,- means on said inner'portion-for operating the first said door upon; rotation of -said shaft, a discon said protruding portion ,andLa handle for rotating" "said .disc' whereby saidfirst door may be .opened or closed, asecond shaft substantiallyparallel with said second 1 door, means on said shaft for operating said second door, a hollow shaft loose about said first shaft, gearing meansbetween said hollow, shaft and second shaft, a'disc on said hollow shaft and a handle vfor rotating said disc wherebysaid second door maybe opened or. closed, said -disc-haying apertures aligned when said doors-are closed, a fixed element, a

7 member slidablelon said fixed element, and a pin carried by, said .member. adapted iat .-alltimes to be within; one or the other of said. apertures.

6. In a furnace chamber'comprising two doors, an operating meansfor one of said doors and c0lnprising a rotatable-member, operating means for the "other, door andcomprising a rotatable member, a pairof gears, reducing gearing-bea as tween ronjepf said rotatablemembers and one ,of said gears reducing' gearing between the other rotatable member and the other of said gears,

saidlgears being substantially parallel and an in;

te rl ock between said gears permitting rotationof one of saidrotatable membersto open the corresponding door only while the other, of said ro tatable inembersis in a predetermined position. I} 7.The structure of claim 6 in which indicators comprising fingers on each ofsaid gears are-proidedto indicate the closedrpo sition-of said doors. 8. The structure of claim 6 in which indicators comprising fingers on each of said gears are pro:

yided to indicate the closed position of said doors,

andmeans are provided'for a lock is operable for maintaining said doors closed while said'indicators so indicate.

,9 Theistructure ofclaim '6 wherein means are provided for, adjusting said gears relative'to saidgearing to insrireoperability of said interlock while the doors are in closed position. f v

lO/A furnace comprising two contiguous -enclosed chambers separated by a wall'including a door, a second doorlin an. outer wall of one of said u chambers, and operating means for said, doors comprising a pair of substantially revoluble mem- 7 13.6175 rotatable in substantially, parallel planes, one

for each; door, means for independently rotating each member. through less .thanJlZQdc-grees to openfand close saiddoors, and aninterlockbejusting said gears 1 relative to said. gearing to insure that said inter-' v tween said rotatable niemberspermit'tingoperationoi one oflsaid'members only while the other islin a redeterminedposition.

QILVA furnace comprising two contiguous enclosed chambers separated by a wall ,including a door, a second door in an 'outer wall of one of said chambers, and operating' means for. said doors comprising. apair' of substantially revoluble mem-f bers rotatable in substantially parallel planes, one for ,each dcor, means for independently rotating each member throughlless than 'IZQdegrees to openfand'cl'ose said doors; and interlock be tween said rotatable members permittingv opera- PAUL o. LoT'rEs. 

